scaffolding

Try here for laws, (in the US), and general safety practices for scaffolding:

http://www.osha.gov/SLTC/scaffolding/index.html

General rules for scaffolding - requires that a freestanding scaffold can be erected at a 1 to 3 ratio. (example: 5' wide equals 15' high). To achieve greater heights the scaffold must be attached or anchored to the structure. Another method of increasing scaffold height would be to use outriggers or extenders. (1 to 3 ratio still applies).

Now to answer your question...It is acceptable to tie into or anchor to the existing scaffold as support when changing direction. This enables the workers to walk from the West elevation to the North elevation in a continuous and safe manner.

Check to see that all scaffold or outrigger bases are on solid ground or that base plates have been installed. In addition to the above requirements scaffolds must be installed horizontally level and with the proper use of cross braces, guard rails, pig tail pins and decks or planks.

Good luck with your project!

I think his question was could they be attaching the new scaffold to the existing one while the workers are on it. Not something I would recommend. Scaffolds are safe once all the pieces of the puzzles are in place. If something happened to the scaffold being erected before it is completed, it would entrain (push/pull) on the existing scaffold and possibly put the workers out of balance (risk of injury). Unless the existing scaffold is safely anchored to the building, I would not climb on the scaffold while they are tying into it.

exactly this is my question. Many thanks for clarifying my question and for your answer.

You're very welcome. Be safe...